internal static long PandigitalPrimeSets(List <long> digits)
{
if (digits.Count == 0)
{
return(1);
}
long count = 0;
digits.Sort();
var maxElement = digits[digits.Count - 1];
var restOfDigits = UtilityFunctions.Complement(new List <long> {
maxElement
}, digits);
var subsets = UtilityFunctions.GenerateSubsets(restOfDigits);
foreach (var subset in subsets)
{
subset.Add(maxElement);
var complement = UtilityFunctions.Complement(subset, digits);
var subsetDigitSignature = UtilityFunctions.DigitSignature(subset, ProblemDigits);
count += PrimeCandidates[subsetDigitSignature].Count * PandigitalPrimeSets(complement);
}
return(count);
}